*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    position: relative;
    background-color: #eee;
    min-height: 1000px;
    margin: 0;
    padding: 0;
}

body::after {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    padding: 6px 22px;
    border-radius: 22px;
    content: attr(data-scale);
    background-color: #000;
    opacity: 0;
    color: white;
    pointer-events: none;
    transition: opacity .5s ease-out;
}

body.wheel::after {
    opacity: 0.5;
}

#app {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    width: 200px;
    height: 200px;
    border: 1px dashed black;
}

#app.is-drag {
    cursor: move;
}
